perf tools: Protect header files with a consistent style

There was a colorful mix of header guards - standardize them.

Signed-off-by: John Kacur <jkacur@redhat.com>
LKML-Reference: <alpine.LFD.2.00.0909241756530.11383@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/util/header.h

@@ -1,5 +1,5 @@
-#ifndef _PERF_HEADER_H
-#define _PERF_HEADER_H
+#ifndef __PERF_HEADER_H
+#define __PERF_HEADER_H
 
 #include "../../../include/linux/perf_event.h"
 #include <sys/types.h>
@@ -44,4 +44,4 @@ perf_header__find_attr(u64 id, struct perf_header *header);
 
 struct perf_header *perf_header__new(void);
 
-#endif /* _PERF_HEADER_H */
+#endif /* __PERF_HEADER_H */